128728702973 has 4 divisors (see below), whose sum is σ = 138630910908. Its totient is φ = 118826495040.

The previous prime is 128728702961. The next prime is 128728703041. The reversal of 128728702973 is 379207827821.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 59468675044 + 69260027929 = 243862^2 + 263173^2 .

It is a cyclic number.

It is not a de Polignac number, because 128728702973 - 2²⁶ = 128661594109 is a prime.

It is a super-3 number, since 3×128728702973³ (a number of 34 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128728707973) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4951103948 + ... + 4951103973.

It is an arithmetic number, because the mean of its divisors is an integer number (34657727727).

Almost surely, 2^128728702973 is an apocalyptic number.

128728702973 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

It is an amenable number.

128728702973 is a deficient number, since it is larger than the sum of its proper divisors (9902207935).

128728702973 is an equidigital number, since it uses as much as digits as its factorization.

128728702973 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9902207934.

The product of its (nonzero) digits is 4741632, while the sum is 56.

The spelling of 128728702973 in words is "one hundred twenty-eight billion, seven hundred twenty-eight million, seven hundred two thousand, nine hundred seventy-three".